Currently, 2nd generation mobile communications technology/3rd generation mobile communications technology (2nd Generation/3rd Generation, “2G/3G”) networks, such as Global System for Mobile communications (Global System of Mobile communication, “GSM”) networks, have been widely deployed in many regions. Therefore, to some extent, 2G/3G networks can be considered to have complete coverage. With the rapid development of communications technologies, new generation evolved networks such as Long Term Evolution (“LTE”) networks have covered some urban areas and traffic hotspot regions, and therefore evolved networks and 2G/3G networks coexist in these areas.
During early deployment of LTE, LTE only supports data services, and does not support voice services. Therefore, operators may use 2G/3G networks to provide voice services for subscribers on the one hand, and may use LTE networks to provide data services for subscribers on the other hand. In order to improve user experience, a terminal may be a multi-transceiver multi-mode terminal that supports single-number dual-camped, where voice services are borne over a GSM network, and data services are borne over an LTE network. The terminal may include a GSM module and an LTE module, where the GSM module may camp on the GSM network, and establish services in the GSM network, and the LTE module may camp on the LTE network, and establish services in the LTE network.
Data services belong to packet switched (Packet Switching, “PS”) domain services, and voice services belong to circuit switched (Circuit Switching, “CS”) domain services. In an area simultaneously covered by a GSM network and an LTE network, a terminal that supports single-number dual-camped accesses the GSM network in a CS domain, and accesses the LTE network in a PS domain, and therefore the terminal can establish a voice service in the GSM network and establish a data service in the LTE network concurrently.
However, in an area only covered by a GSM network, a terminal can access the GSM network in both the CS domain and the PS domain, but whether the terminal can establish a voice service and a data service concurrently needs to be determined by capabilities of the terminal and capabilities of the GSM network. In addition, only when both the terminal and the GSM network support the dual transmission mode (“DTM”) can the terminal establish a voice service and a data service concurrently. Otherwise, the terminal will suspend a service, and generally, the terminal will suspend the data service.
An LTE network generally has partial coverage during early network deployment, and generally only covers urban areas or hotspot areas. Because complete coverage is not yet realized, when a terminal that supports single-number dual-camped leaves the LTE network, the terminal needs to reselect or be handed over to a target GSM cell. Therefore, an appropriate solution is required to support an user equipment in reselecting or being handed over to an appropriate target cell.